The Easiest Way to Understand Ohm’s Law

Ohm’s law describes the amount of resistance the current has to face while it travels between two points.

DefinitionOhm’s law states that the current through a conductor between two points is directly proportional to the voltage across the two points, given that the physical conditions such as length of wire, temperature etc remain constant.

What’s actually happening:

When electrons flow through a conductor (say, a wire) they collide with each other, thus losing some energy in the form of heat (that’s why a wire feels hot when current is allowed to pass through it, this is known as the heating effect of electric current).

Charge (the green guy) needs the energy to go from one point to another. This energy is provided due to the potential difference between those two points. That is the work done in helping the poor current to travel between those two points is our yellow guy. Then enters the resistance (the red guy) which is nothing but the opposition due to the collision of electrons. This is a never-ending fight, which continues as long as there is resistance in the wire and which will always be there (except in the case of superconductors).

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Resistance depends upon factors such as the length of the conductor, the area of cross section of the conductor and temperature of the conductor.

Note that it’s not a positive charge that flows. It’s the electrons that actually flow. Positive charges are bound to the nucleus. We say that current has an opposite direction to that of electrons just because in earlier years it was believed that it’s the positive charge that makes the current. So, it has become a convention to use the direction opposite to electron flow as the direction of the current.

You see change is difficult to implement and adapt to

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